OOPS! A Port Authority patrol boat sinks off Breezy Point, Queens, after an underwater hatch was opened on board. Photo:

OOPS! A Port Authority patrol boat sinks off Breezy Point, Queens, after an underwater hatch was opened on board.

OOPS! A Port Authority patrol boat sinks off Breezy Point, Queens, after an underwater hatch was opened on board. (
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A $500,000 Port Authority patrol boat sank this month after a veteran police sergeant took the advice of a clueless civilian safety instructor — and opened a hatch while it was under water, The Post has learned.

“It was like opening a window during a carwash,” one PA insider lamented of the screw-up off Breezy Point, Queens, that left 11 people scrambling for their lives.

Nobody was seriously injured, but eight cops and three civilians had to either swim to safety or be rescued as the 37-foot M-2 model Moose Boats craft sank 40 feet to the ocean floor about 300 yards off shore.

PA sources said the sergeant who ordered the hatch open is expected to face disciplinary action. They refused to identify him. He will likely lose vacation days for failing to maintain supervisory control and basically abdicating his command to a civilian during the Sept. 9 debacle, they said.

The aluminum-hull catamaran was being used for rescue exercises mandated by the Federal Aviation Administration for airport first responders, a source said.

The boat, PAPD No. 7211, was among those on hand to respond to potential terror maritime assaults on JFK Airport and possible airline crashes in Jamaica Bay.